Bussed electrical centers (BECs) (also known as power distribution centers or junction blocks) are commonly used in automotive vehicles to simplify electrical system wiring by eliminating multi-branch wiring and consolidating fuses, relays, and other electrical circuit components in a single location. A BEC typically comprises a plastic case having a multitude of sockets formed therein for receiving the circuit components. The case contains bus bars or other conductive means for interconnecting and supplying power to the various circuit components. Electrical connectors are disposed on the BEC to receive mating connectors which terminate wire harness which extend throughout the vehicle to interconnect the circuitry of the BEC with the numerous electrical systems and devices elsewhere in the vehicle.
BECs are often located within the engine compartment of the vehicle, and so are fitted with upper and lower housings to protect the BEC from contaminants such as dirt, water and other debris. The lower housing is typically bolted or otherwise secured to some structure within the engine compartment and thus serves as a mounting bracket for the BEC. Since the BEC must be readily accessible for inspection and servicing, it is normally positioned near the top of the engine compartment with all of the replaceable circuit components disposed on its upper surface beneath an upper housing which is removable to provide access. As the number and complexity of vehicle electrical systems have increased in recent years, the number of circuit components in a BEC has grown to occupy most or all of the surface area on the upper surface of the BEC. Consequently, it has become common practice to locate one or more of the BEC electrical connectors on the lower surface of the BEC, thus freeing more of the upper surface for placement of circuit components.
Some wiring harness connectors are quite large, containing several dozen terminals. In some cases, two or more wiring harness connectors are inserted into a bracket to form one large connector which is then secured to a large, composite BEC connector in a single operation, thus saving time in the assembly process. A large wiring harness connector is usually secured to its mating BEC connector by means of a captive bolt passing through the center of one of the connectors and engaging a nut molded into the mating connector. Tightening the bolt draws the two connectors into electrical contact with one another, an operation that would be difficult to perform by hand due to the large insertion forces that accompany connectors with large numbers of terminals.
It is common practice in the automotive industry for the BEC to be manufactured at a first plant and shipped to a vehicle assembly plant where the BEC is installed in the vehicle and the necessary wire harness connections are made thereto. When a connector is located on the lower surface of the BEC, the limited amount of space in most engine compartments often makes it difficult or impossible to reach the bottom of the BEC and make such a connection after the BEC has been secured in it's operational position in the engine compartment.
Accordingly, connections to the bottom of the BEC are made prior to securing it in the engine compartment. This requires an assembly line worker to hold the BEC upside down, position the wire harness connector in alignment with the mating connector on the lower surface of the BEC, drive the captive bolt into engagement with the nut, then flip the BEC back upright and secure it into its operational position in the engine compartment. This procedure is very awkward and time consuming, and increases the chance of accidental damage to the connectors and other components involved.